1. Field of the Invention
The present invention relates to a CRT (Cathode Ray Tube) based display system and more particularly to a CRT based display system with a display system processor integrated in a single chip. Inclusion of analog functions in this IC (Integrated Circuit) significantly lower system cost and enhance display capability.
2. Description of the Prior Art
In present day design, Cathode Ray Tube (CRT) based display systems are controlled primarily by analog circuit. Horizontal deflection control circuit and vertical deflection control circuit are constructed via analog components or analog integrated circuit. On the other hand, digital display system controller is used for managing all aspect of the display attributes and control of deflection circuit for digital controlled monitor. The digital display system controller typically consists of a microprocessor, associated memory, and control software that is processed via a conventional low cost digital semiconductor processor. This controller typically interfaces with deflection analog circuit via two methods. The first method is to provide an analog interface to the deflection analog circuit. The second method is to provide a digital interface to the digital section of such analog circuit. Thereof, deflection related parameters such as horizontal size, horizontal centering, vertical size and vertical centering can be changed.
For on screen display (OSD) application, a separate integrated circuit controller is used to generate the necessary video information. Digital display system controller must communicate video content and video position information to the OSD chip.
FIG. 1 shows a block diagram of conventional display control system. A digital display system controller 101 controls display front panel 107, power supply 108, video processor 106, power video circuit 111, on screen display (OSD) processor 105, vertical processor 104, and horizontal processor 103. Each block mentioned above consists of individual electric circuit. Power horizontal deflection circuit 109 controls horizontal deflection through horizontal yoke (H. yoke), and generates a flyback pulse 102 to the horizontal processor 103. Power vertical deflection circuit 110 couples with the vertical processor 104 and controls vertical deflection through vertical yoke (V. yoke).
Current technology requires individual integrated circuit (IC) for deflection control, on screen display (OSD) generation, and digital display system controller. Due to different process technology used in these ICs, there is no single IC that integrates digital display system controller with deflection control, and no single IC that integrates digital display system controller with an OSD processor.